Automatic toothbrush with a fluid motor

ABSTRACT

An automatic toothbrush having a fluid motor, in particular a water motor, which produces reciprocating movements of a part, such as a piston, coupled to the brush proper, one or more ports being located in the fluid supply passage and/or the fluid discharge passage, which ports can periodically be opened and closed by a member, such as a slide, which is driven by a switching mechanism the position of which is determined by the position of the pistons. Preferably a buckling spring mechanism is used.

United States Patent Potters et al.

[4 1 Feb. 22, 1972 AUTOMATIC TOOTHBRUSH WITH A FLUID MOTOR Inventors: Cornelis Johannes Theresla Potters; .lacobus Pieter Relnhoudt; iiendricus Franclscus Gerardus Smulders, all of Emmasingel, Eindhoven. Netherlands Assignee: U.S. Philips Corporation, New York, N.Y.

Filed: Jan. 26, 1970 Appl. No.: 5,739

Foreign Application Priority Data Jan. 24, 1969 Netherlands ..6901274 U.S. Cl. ..l5/22 R, 91/346 Int. Cl. ..A46b 13/02 Field ofSearch ..15/22 R, 22 C;91/218, 346,

[56] References Cited UNITED STATES PATENTS 3,213,471 10/1965 Freeman ..l5/22 R Primary Examiner-Edward L. Roberts Attorney-Frank R. Trifari [57] ABSTRACT 9 Claims, 3 Drawing Figures SHEET 1 BF 2 nl nl swmmm INVENTORS CORNELIS J.T. POTTERS A CO US PFREINHOUDT BY ND ICUS .G. SMULDERS AUTOMATIC TOOTHBRUSII WITH A FLUID MOTOR The invention relates to an automatic toothbrush provided with a fluid motor for producing reciprocating movements. The motor has at least one chamber which acts as a power chamber having a movable wall.

Such a motor is to be understood to mean any motor in operation a movable wall moves along a given path on increase of the volume of the power chamber and moves in the opposite direction along substantially the same path on decrease of the volume.

US. Pat. No. 3,213,471 describes an automatic toothbrush of this kind which is equipped with a water motor. The appliance can be connected to the water supply mains by means of a hose; the energy required for the brushing action is supplied by the pressurized water of the water supply mains. The motor comprises a fluid oscillator of the type in which a fluid flow can be switched from one state to the other under the sole action of the fluid itself. The fluid oscillator is provided with two output passages of which one is connected to the power chamber and the other to the discharge port of the motor. Switching the fluid flow back and forth is effected by means of two control jets which each are tapped from the main flow in the output passages by way of a feedback passage having a given fluid resistance and a given fluid capacity. The frequency of the oscillator depends on its geometry and upon the pressure and the density of the fluid supplied.

The frequency of the oscillator of this known device is determined by the velocity at which the fluid signal propagates in the feedback passage. The velocity, in a first approximation, is equal to the velocity of sound in the respective fluid, in this case water. Hence, pressure pulses of very short duration will be applied to the power chamber, and during these short periods only small amounts of water will be able to flow to the power chamber and therefore the fluid oscillator will have a high frequency.

It is an object of the invention to provide a fluid-operated toothbrush that does not have the same result. This is accomplished by providing a fluid-operated toothbrush having a fluid motor with at least one port located in the fluid path between the fluid supply and the motor, and a bistable switch for cyclically opening and closing the port. The switch is controlled by the displacement of a movable wall in a power chamber of the fluid motor.

The bistable switch of the invention is to be understood to mean a device the input signal to which is the position of the movable wall of the power chamber or another position directly related thereto and the output signal or output signals of which can have only two values which correspond to a logical or a logical l. The device further has the property that switching takes place only if the input signal either exceeds a high limit or falls below a low limit. The switching action in the case of exceeding a high limit taking place only if the preceding switching action of the switch was due to the signal falling below the low" limit, whereas the switching action in the case of the signal falling below the low limit takes place only if the preceding switching of the switch was due to the exceeding of the high" limit.

Assigning the predicate high" to one of the limits and the predicate low to the other limit is arbitrary.

It is important that the construction of the automatic toothbrush be as simple as possible since they are massproduced and its cost therefore becomes significant. This means that the fluid motor must have a simple construction. A low cost is obtainable with the present invention by using a mechanical switch for the bistable switch of the fluid motor.

The bistable mechanical switch adapted to be controlled by the movements of the movable wall is a device which consumes mechanical energy and has at least one energy-accumulating element. At an appropriate instant the energy-accumulating element gives off its energy so as to change the state of the mechanical switch.

A requirement for satisfactory operation of an automatic toothbrush is that the brush reciprocate at a frequency of a few tens of Herz. Hence, the component parts of the mechanical bistable switch must have small masses, and further the switch must satisfy the requirement of having a low cost price.

The above mentioned requirements: are largely satisfied by an embodiment of the present invention which is characterized in that the bistable mechanical switch comprises a substantially rod-shaped spring which has a buckled configuration, a portion of the spring cooperating with means for opening and closing at least one port, while another portion is coupled with each movable wall of each power chamber.

For a rod-shaped spring to be buckled two points of the spring must be brought together so that the distance between the two points becomes smaller than in the nonbuckled condition of the spring. Hence, forces must be exerted on the said points of the spring in the direction of the line joining these points.

An embodiment intended to prevent the production of undesirable frictional forces in the motor due to the above-mentioned forces is characterized in that the axial buckling forces of the spring are substantially exclusively absorbed by parts of the bistable switch itself and/or fixed parts of the automatic toothbrush.

In some cases an embodiment is preferable which is characterized in that it includes means for adjusting the degree of buckling of the spring.

In such an embodiment the frequency and/or the torque of the fluid motor is adjustable because a change in the degree of buckling involves a change in the characteristic of the spring.

A further embodiment combines structural simplicity with a comparatively high power to be generated and is characterized in that the motor has two aligned power chambers the movable walls of which are constituted by the end surfaces of a single double-acting piston and in that the motor has a single double-acting slide member capable of opening and closing a primary port in the fluid supply path and a primary port in the fluid discharge path for each of the power chambers.

An embodiment which is important especially in view of the possibility of cheap mass manufacture of a mass product such as the automatic toothbrush concerned is characterized in that the chambers and passages of the fluid motor have been formed in a number of stacked plates of substantially selfreleasing shapes, which plates are made of a material which is impermeable to fluid and are locally in fluid communication with one another. As a result, the various component parts of the automatic toothbrush can be made from a synthetic material by means of injection moulding and can readily be assembled.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:

FIG. 1 is a partial bottom plan view, and partial sectional view taken on the line X-X of F IIG. 2 of an automatic toothbrush according to the invention provided with a water motor having a double-acting piston and a double-acting slide member,

FIG. 2 is a side view of the toothbrush of FIG. 1, and

FIG. 3 is an exploded view of the toothbrush shown in FlGS. l and 2.

In all the figures similar reference characters relate to like parts. The two power chambers of the water motor shown are designated by l and 2. Each power chamber has a movable wall 3 and 4 respectively. The water, which may be taken from the public supply mains and which drives the motor, is sup plied through a water supply aperture 5 and discharged through a water discharge aperture 6 formed in hose pillars 7 and 8 respectively.

On the part of the trajectory of the water through the motor from the supply aperture 5 through the power chamber 1 to the discharge aperture 6, along which trajectory the water always flows in substantially the same direction during the operation of the motor, two closable primary ports 9 and 10 are located; 9 is the inlet port and 10 is the outlet port. An inlet port 11 and an outlet port 12 are provided for the power chamber 2. Water enters through hose pillar 7, its opening 5 communicates with opening 35 in component part 25. Opening 35 communicates through channels 36 and 37 within component part 25 with opening 38 and thus with through-hole 39 in part 24 which in turn opens into V-shaped duct 40 in component part 23. Duct 40 communicates with a duct 41 in component part 28 via through-holes 42, 43, 44 and 45 in component parts 24, 25, 26 and 27 respectively. Port 11 communicates with duct 41.

Port 9 in part 24 communicates with duct 40 in part 23 and port in part 25 as well as with a duct 46. Duct 46 communicates with elongated aperture 47 in part 24, which in turn communicates with power chamber 1.

Similarly port 11 in part 27 communicates with duct 41 in part 28 and port 12 in part 26 as well as with a duct 48. Duct 48 communicates with elongated aperture 49 in part 26 which communicates with power chamber 2.

The central duct 50 in part 26 communicates with both outlet ports 10 and 12 and also via a further duct 51 and a channel 55 with opening 52 in part 26. Hose pillar 8 is fastened in opening 52, which thus communicates with outlet opening 6.

In order for water to reach power chamber 1, the water is supplied through a supply hose 53 connected to hose pillar 7, thence through hose pillar 7, opening 35, channel 36, opening 38, through-hole 39, duct 40, inlet port 9, duct 46, elongated aperture 47.

In order for water to reach power chamber 2, the water is supplied through the hose 53 and thence through hose pillar 7, opening 35, channel 36, opening 38, through-hole 39, duct 40, through-holes 42, 43, 44 and 45, duct 41, inlet port 11, duct 48, elongated aperture 49.

In order for the water to be discharged from power chamber 1, it passes through elongated aperture 47, duct 46, outlet port 10, central duct 50, duct 51, channel 55, hose pillar 8, opening 6, discharge hose 54.

In order to discharge the water from power chamber 2, it passes through elongated aperture 49, duct 48, outlet port 12, central duct 50, duct 51, channel 55, hose pillar 8, opening 6, discharge hose 54.

The two inlet ports 9 and 11 and the two outlet ports 10 and 12 can be closed under the influence of a bistable switch in the form of a mechanical switch which is controllable by the movements of the movable walls 3 and 4. The switch mainly comprises a rod-shaped spring 13, which in view of its small thickness will hereinafter be referred to as a leaf spring. A part 14 of the leaf spring cooperates with a double-acting slide member which serves to open and close the ports 9, 10, 11 and 12, and a part 16 is coupled to the movable walls 3 and 4 of the power chamber which form part of a double-acting piston 17. Slide member 15 is notched at 63, this notch cooperates with notch 64 in part 14 of the leaf spring 13. Notch 65 in double-acting piston 17 cooperates with end side 66 of leaf spring 13.

The axial buckling forces of the leaf spring 13 are absorbed by a pin l8 and a block 19. Pin 18 is accommodated in holes 56 and 57 of parts 25 and 26 respectively. Pin 18 is notched at 58, this notch cooperates with the side 59 of the rectangular aperture 60 in leaf spring 13. Block 19 is notched at 61, this notch cooperating with the end side 62 of leaf spring 13. The notches have been made so that the leaf spring can buckle from one side to the other substantially without friction.

The block 19 is displaceable so as to permit adjustment of the degree of buckling of the spring 13. This displacement of the block 19 can be effected by means of a screw arranged in a plate 21. Plate 21 is fastened to parts and 26 by two screws 67-68, passing through holes 69 and 70 in plate 21 and screwed into threaded holes 71 and 72. A rubber packing 73 is interposed between plate 21 and the parts 25 and 26 and is provided with holes 74-76 corresponding to the holes 69, 77 and 70 in plate 21. Hole 77 is threaded and accommodates screw 20. which is locked by a unit 78.

The entire water motor is accommodated in a handle 22 of the toothbrush; the chambers and passages have been formed in a number of stacked component parts 23-28 made of water-impermeable material which are locally in water communication with one another and all have self-releasing shapes. These parts may be secured to one another in any of the known manners; the drawings do not show anything in this respect.

The brush proper 29 is secured to the end of a driving shaft 31 which is supported in a part 30 integral with the part 26. The brush 29 is driven by the double-acting piston 17 through a crank-slot mechanism comprising a slot 32 in the doubleacting piston 17 and a crank pin 34 secured to a disc 33. The studs 79 and 80 secured to parts 23 and 28 respectively serve as end-stops for piston 17.

The operation of the automatic toothbrush shown is as follows: in the position of the water motor shown in FIG. 1 the ports 9 and 12 are closed and the parts 10 and 11 are open. Thus, the power chamber 2 communicates with the water supply aperture 5, through the ducts and channels described above, and the power chamber 1 communicates with the water discharge aperture 6 as described above. As a result, a force directed to the right-hand side is exerted on the doubleacting piston 17 so that the piston will move to the right against the force exerted on it by the leaf spring 13. Consequently, the leaf spring 13 is tensioned and will reach a state of unstable equilibrium just before the double-acting piston reaches its extreme right-hand position. On further movement of the double-acting piston the leaf spring buckles rapidly from one side to the other while using its stored energy at least in part to displace the double-acting slide member 15 from right to left with the result that the power chamber 1 is closed with respect to the water discharge and is connected to the water supply, and the power chamber 2 is connected to the water discharge and is closed with respect to the water supply. The further sequence of movements will now be clear.

What is claimed is:

1. A vibrating fluid-powered toothbrush comprising a handle, a brush member connected to said handle and arranged for vibrating motion with respect thereto, a fluid motor housed within said handle for driving said brush, said motor comprising a pair of power chambers, a movable wall hounding one side of each chamber, a fluid supply duct for supplying fluid under pressure to said handle, a fluid discharge duct for discharging fluid from said handle, a fluid path connecting said supply duct to said chambers of said motor and the chambers with said discharge duct, a pair of inlet ports arranged in the fluid path for passing fluid through to said chambers, a pair of outlet ports in the path for passing fluid from the chambers to the discharge duct, a bistable mechanical switch the operation of which is controlled by the displacements of said movable walls, said switch arranged for controlling the opening and closing of said inlet and outlet ports so that fluid is alternately supplied to and discharged from said pair of chambers, and means connecting said movable wall to said brush for causing oscillatory vibrating motion thereof.

2. The vibrating fluid-powered toothbrush according to claim 1 wherein the movable walls of the pair of power chambers comprise opposite and surfaces of a single double-acting piston, and further comprising a single double-acting slide member arranged for opening and closing said inlet and outlet ports, said slide member being actuated by the movement of said bistable switch.

3. A vibrating fluid-powered toothbrush comprising a handle, a brush member connected to said handle and arranged for vibratory movement with respect to the handle, a fluid motor in said handle causing vibratory motion of said brush, said motor comprising at least one power chamber, a movable wall formed as one side of said power chamber, a fluid supply channel supplying fluid to said chamber, a fluid discharge channel for discharging fluid from said chamber, at least a first port arranged in the fluid path, movable means arranged for cyclically opening and closing said port, a bistable switch being operated by the displacement of said movable wall, said switch arranged for controlling the operation of said movable means, and means connecting said movable wall to said brush for causing oscillatory vibrating motion thereof.

4. The vibrating fluid-powered toothbrush according to claim 3 wherein said bistable switch is a mechanical switch.

5. The vibrating fluid-powered toothbrush according to claim 4 wherein said fluid motor comprises a pair of power chambers each having a movable wall, said movable walls of said chambers forming opposite end surfaces of a single double-acting piston, and further comprising a fluid supply channel and a fluid discharge channel being provided for each of said chambers, said first port being arranged in the supply channel of each of said chambers, a second port arranged in the discharge channel for each of said power chambers, and wherein said movable means comprises a single double-acting slide member arranged for opening and closing the first and second ports respectively of said power chambers.

6. The vibrating fluid-powered toothbrush according to claim 5 wherein said bistable mechanical switch comprises a substantially rod-shaped spring having a buckled configuration, at least part of said spring cooperating with said doubleacting slide member and another part of said spring being coupled to each movable wall of said power chambers,

7. The vibrating fluid-powered toothbrush according to claim 6 wherein the axial buckling forces of said spring are substantially absorbed by fixed parts of the toothbrush.

8. The vibrating fluid powered toothbrush according to claim 7 further comprising means for adjusting the degree of buckling of said rod-shaped spring.

9. The vibrating fluid-powered toothbrush according to claim 8 wherein the chambers and passages of the fluid motor are defined within a plurality of stacked plates in local relative fluid communication, said stacked plates being made of a fluid-impermeable material, said plates having shapes which are substantially self-releasing. 

1. A vibrating fluid-powered toothbrush comprising a handle, a brush member connected to said handle and arranged for vibrating motion with respect thereto, a fluid motor housed within said handle for driving said brush, said motor comprising a pair of power chambers, a movable wall bounding one side of each chamber, a fluid supply duct for supplying fluid under pressure to said handle, a fluid discharge duct for dIscharging fluid from said handle, a fluid path connecting said supply duct to said chambers of said motor and the chambers with said discharge duct, a pair of inlet ports arranged in the fluid path for passing fluid through to said chambers, a pair of outlet ports in the path for passing fluid from the chambers to the discharge duct, a bistable mechanical switch the operation of which is controlled by the displacements of said movable walls, said switch arranged for controlling the opening and closing of said inlet and outlet ports so that fluid is alternately supplied to and discharged from said pair of chambers, and means connecting said movable wall to said brush for causing oscillatory vibrating motion thereof.
 2. The vibrating fluid-powered toothbrush according to claim 1 wherein the movable walls of the pair of power chambers comprise opposite end surfaces of a single double-acting piston, and further comprising a single double-acting slide member arranged for opening and closing said inlet and outlet ports, said slide member being actuated by the movement of said bistable switch.
 3. A vibrating fluid-powered toothbrush comprising a handle, a brush member connected to said handle and arranged for vibratory movement with respect to the handle, a fluid motor in said handle causing vibratory motion of said brush, said motor comprising at least one power chamber, a movable wall formed as one side of said power chamber, a fluid supply channel supplying fluid to said chamber, a fluid discharge channel for discharging fluid from said chamber, at least a first port arranged in the fluid path, movable means arranged for cyclically opening and closing said port, a bistable switch being operated by the displacement of said movable wall, said switch arranged for controlling the operation of said movable means, and means connecting said movable wall to said brush for causing oscillatory vibrating motion thereof.
 4. The vibrating fluid-powered toothbrush according to claim 3 wherein said bistable switch is a mechanical switch.
 5. The vibrating fluid-powered toothbrush according to claim 4 wherein said fluid motor comprises a pair of power chambers each having a movable wall, said movable walls of said chambers forming opposite end surfaces of a single double-acting piston, and further comprising a fluid supply channel and a fluid discharge channel being provided for each of said chambers, said first port being arranged in the supply channel of each of said chambers, a second port arranged in the discharge channel for each of said power chambers, and wherein said movable means comprises a single double-acting slide member arranged for opening and closing the first and second ports respectively of said power chambers.
 6. The vibrating fluid-powered toothbrush according to claim 5 wherein said bistable mechanical switch comprises a substantially rod-shaped spring having a buckled configuration, at least part of said spring cooperating with said double-acting slide member and another part of said spring being coupled to each movable wall of said power chambers.
 7. The vibrating fluid-powered toothbrush according to claim 6 wherein the axial buckling forces of said spring are substantially absorbed by fixed parts of the toothbrush.
 8. The vibrating fluid powered toothbrush according to claim 7 further comprising means for adjusting the degree of buckling of said rod-shaped spring.
 9. The vibrating fluid-powered toothbrush according to claim 8 wherein the chambers and passages of the fluid motor are defined within a plurality of stacked plates in local relative fluid communication, said stacked plates being made of a fluid-impermeable material, said plates having shapes which are substantially self-releasing. 